This invention relates to cutting apparatus, and more particularly to apparatus for dicing continuous sheet material into relatively small, quadrilateral pieces.
Some arts related to continuous sheet formation require minimal processing of the sheet material after it is formed. Others require substantial alteration of the material to convert it to a usable configuration. Reconstituted tobacco is manufactured by processes analagous to the paper-making art, and the product emerges in a continuous sheet, which must then be cut into small pieces approximately the size and shape of tobacco strips.
Conventionally, cutting apparatus consists of two sets of knives. Slitter knives, located immediately downstream from the sheet drying station, slice the sheet longitudinally. The resulting ribbons are then cut transversely by a reel cutter, fabricated much like a large reel-type lawnmower blade. Generally, this apparatus is difficult to maintain, as the blades are relatively inaccessible. Consequently, the blades often become gummy, reducing their efficiency and producing uneven cuts. Also this device inherently produces a high level of dust and fines, leading to added costs and reduced output. Morever, this design is limited in width, making it difficult to adapt to modern high-width drying equipment.
An improved apparatus is disclosed by Honeycutt in U.S. Pat. No. 3,713,358. In that device, sheet material first is slit and then cross-lapped onto a conveyor moving transverse to the previous direction of travel by a traversing vertical conveyor. The end of this traversing conveyor adjacent the slitter knives pivots, and the other end oscillates above the transverse conveyor. Another set of slitter knives at the end of the transverse conveyor cuts the cross-lapped material into parallelogram-shaped pieces.
This device offers improved performance over the conventional method, but at the price of increased space requirements to accommodate the transverse conveyor. Also, the preferred embodiment teaches the use of vacuum means to hold material on the traversing conveyor; this system entails relatively high energy requirements and results in the traversing conveyor being bulky.
Thus, the tobacco industry remains in need of apparatus to cut reconstituted tobacco, without increasing space or energy requirements over conventional methods.